MAX98389 Breakout Board and Drivers

The MAX98389 is an interesting audio amplifier chip – mainly due to its audio-rate current sensing abilities.

The amplifier has a digital audio input (with up to 96kHz sample rate) to connect with a microcontroller or singleboard computer (using i2s or TDM) but also has a digital audio return - where the sensed current and modelled voltage output signal can be send back out.

This feature opens up a load of new possibilities - from running diagnostics on loudspeakers, to using the speaker itself as a sensor, to sensing the resonant frequency of a linear resonant actuator (LRAs are commonly used for haptic feedback).

The issue with this chip is that a) it is only available as a BGA part (difficult to hand solder) and b) it uses 1.8V logic levels (most hobbyist microcontrollers and SBCs use 3.3V or possibly 5V). These two factors make it difficult to directly integrate the chip into a hobbyist design.

For these reasons, I have designed a breakout board for the chip that includes the MAX98389 alongside level shifting circuitry and the other extra components required for it to function.

This board is based on my work using the MAX98389 in the HaptiCoupler in which I use it to simultaneously sense and actuate haptic vibrations.

I have also written an Arduino library for the chip - making it easy to get start with pretty much any board that supports i2s audio I/O (a Teensy 4.0 or 4.2 is a good starting point). I’ll be adding to the examples with other board in due course, and hopefully adding libraries for other platforms such as micropython.

This page will be updated soon with more details on this board - and how to purchase it if you’re interested!